The present invention relates to a multilayer piezoelectric element, a fuel injectors having the multilayer piezoelectric element and a method for producing the multilayer piezoelectric element.
Japanese Laid-Open Patent Publication No. 2000-269562 proposes a multilayer piezoelectric element that includes a piezoelectric layer unit having sintered piezoelectric ceramic layers and electrode layers alternately stacked together or a plurality of such piezoelectric layer units assembled in the direction of layer stacking. This type of multilayer piezoelectric element is suitably used as a sensor element to detect vibrations or pressure changes or used as a piezoelectric actuator to cause a displacement or vibrations through the application of a direct-current voltage or an alternating-current voltage. The piezoelectric actuator is fit for a wide range of uses such as an ultrasonic motor, a fuel injector and a precision positioning device.
In order to obtain a high output from the multilayer piezoelectric element, it is conceivable to provide a large number of piezoelectric ceramic layers and electrode layers in the piezoelectric layer unit and/or to provide a large number of piezoelectric layer units in the unit assembly.